| 1. |
- Bidleman, Terry F, et al.
(författare)
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Chiral Pesticides in Soil and Water and Exchange with the Atmosphere
- 2002
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Ingår i: TheScientificWorldJOURNAL. - : Hindawi Limited. ; 2, s. 357-373
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Tidskriftsartikel (refereegranskat)abstract
- The enantiomers of chiral pesticides are often metabolised at different rates in soil and water, leading to nonracemic residues. This paper reviews enantioselective metabolism of organochlorine pesticides (OCPs) in soil and water, and the use of enantiomers to follow transport and fate processes. Residues of chiral OCPs and their metabolites are frequently nonracemic in soil, although exceptions occur in which the OCPs are racemic. In soils where enantioselective degradation and/or metabolite formation has taken place, some OCPs usually show the same degradation preference — e.g., depletion of (+)trans-chlordane (TC) and (-)cis-chlordane (CC), and enrichment of the metabolite (+)heptachlor exo-epoxide (HEPX). The selectivity is ambivalent for other chemicals; preferential loss of either (+) or (-)o,p?-DDT and enrichment of either (+) or (-)oxychlordane (OXY) occurs in different soils. Nonracemic OCPs are found in air samples collected above soil which contains nonracemic residues. The enantiomer profiles of chlordanes in ambient air suggests that most chlordane in northern Alabama air comes from racemic sources (e.g., termiticide emissions), whereas a mixture of racemic and nonracemic (volatilisation from soil) sources supplies chlordane to air in the Great Lakes region. Chlordanes and HEPX are also nonracemic in arctic air, probably the result of soil emissions from lower latitudes. The (+) enantiomer of a-hexachlorocyclohexane (a-HCH) is preferentially metabolised in the Arctic Ocean, arctic lakes and watersheds, the North American Great Lakes, and the Baltic Sea. In some marine regions (the Bering and Chukchi Seas, parts of the North Sea) the preference is reversed and (-)a-HCH is depleted. Volatilisation from seas and large lakes can be traced by the appearance of nonracemic a-HCH in the air boundary layer above the water. Estimates of microbial degradation rates for a-HCH in the eastern Arctic Ocean and an arctic lake have been made from the enantiomer fractions (EFs) and mass balance in the water column. Apparent pseudo first-order rate constants in the eastern Arctic Ocean are 0.12 year-1 for (+)a-HCH, 0.030 year-1 for (-)a-HCH, and 0.037 year-1 for achiral ?-HCH. These rate constants are 3–10 times greater than those for basic hydrolysis in seawater. Microbial breakdown may compete with advective outflow for long-term removal of HCHs from the Arctic Ocean. Rate constants estimated for the arctic lake are about 3–8 times greater than those in the ocean.
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| 2. |
- Khani, Bahram Rashid, et al.
(författare)
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Reproducibility and validity of major dietary patterns among Swedish women assessed with a food-frequency questionnaire
- 2004
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Ingår i: Journal of Nutrition. - : Elsevier BV. - 0022-3166 .- 1541-6100. ; 134:6, s. 1541-5
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Tidskriftsartikel (refereegranskat)abstract
- Defining dietary patterns by factor analysis is an alternative approach to dietary assessment that has been used recently to examine diet-disease relations. However, only 1 study evaluated the reproducibility and validity of this method. Our aim was to assess both the validity and reproducibility of major dietary patterns based on data from a 60-item FFQ. We chose 2 independent random samples among over 60,000 women aged 40-74 y participating in the Swedish Mammography Cohort (SMC). In the validation study, the FFQ was compared with 4 7-d dietary records (DRs) among 129 women. For the reproducibility study, the FFQ was administered twice, 1 y apart in 212 women. By conducting factor analysis, 3 major dietary patterns were identified: healthy (high in vegetables, fruits, fish, poultry, tomato, cereal, and low-fat dairy products), Western (processed meat, meat, refined grains, sweets, and fried potatoes), and drinker (beer, wine and liquor, snacks) pattern. These 3 patterns explained 29-34% of the total variance in these 2 studies. The Spearman correlation coefficients between FFQ1 and FFQ2 (reproducibility) for healthy, Western, and drinker pattern were 0.63, 0.68, and 0.73, respectively (all P < 0.0001). Correlation coefficients between the FFQ and DRs (validity) for these patterns were 0.59, 0.50, and 0.85, respectively (all P < 0.0001). Our results indicate that identification of dietary patterns through factor analysis is a reproducible and valid method. The dietary patterns approach might be used in nutritional epidemiology as an alternative method of dietary assessment.
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| 3. |
- Moody, Sandra A., et al.
(författare)
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The direct effects of UV-B radiation on Betula pubescens litter decomposing at four European field sites
- 2001
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Ingår i: Plant Ecology. - 1573-5052. ; 154:1-2, s. 27-36
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Tidskriftsartikel (refereegranskat)abstract
- A co-ordinated series of field experiments were conducted to consider the effects of elevated UV-B radiation applied directly to decomposing plant litter. Betula pubescens was decomposed under ambient and elevated UV-B (simulating a 15% ozone depletion) using outdoor irradiation facilities at Adventdalen, Norway (78° N), Abisko, Sweden (68° N), Amsterdam, The Netherlands (52° N,) and Patras, Greece (38° N). There was no significant effect of treatment on mass loss for samples collected after 2, 12 and 14 months decomposition at Amsterdam, or after 4 months decomposition at Adventdalen. Significant reductions in the mass loss of litter decomposing under elevated UV-B compared to ambient were found at the other 2 sites. The only effect of treatment on litter chemistry during decomposition was a significant reduction in the N concentration of material at Abisko and a significant increase in C:N at Patras for litter decomposing under elevated UV-B. Significant differences were found in the structure of the fungal community decomposing litter in Sweden, the only site to be tested. These data, and the few published studies of the response of decomposition to UV-B incident on litter suggest that, in the ecosystems and climates that have been studied, such direct effects are typically confined to the initial stages of decomposition, and are rather small in magnitude.
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| 4. |
- Terry, Paul, et al.
(författare)
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Body weight and colorectal cancer risk in a cohort of Swedish women : relation varies by age and cancer site
- 2001
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Ingår i: British Journal of Cancer. - : Springer Science and Business Media LLC. - 0007-0920 .- 1532-1827. ; 85:3, s. 346-349
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Tidskriftsartikel (refereegranskat)abstract
- The relation between relative body weight and colorectal cancer among women is unclear. In a large prospective cohort study, we found a positive association only for distal cancers among younger women that became attenuated at older ages. These results support previous reports in which results were stratified by age or colorectal cancer site.
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| 5. |
- Terry, Paul, et al.
(författare)
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Coffee consumption and risk of colorectal cancer in a population-based prospective cohort of Swedish women
- 2001
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Ingår i: Gut. - : BMJ. - 0017-5749 .- 1468-3288. ; 49:1, s. 87-90
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The presumed protective effect of coffee consumption on colorectal cancer, which is supported by case control studies, has not been confirmed in prospective cohort studies. Cohort studies are few in number however and often suffer from a small number of cases, limited attention to confounding variables, and a low percentage of heavy coffee drinkers. METHODS: We examined data from a large population based cohort of Swedish women who were free from cancer at the start of follow up, with a wide range of coffee consumption, information on many potentially confounding variables, and a larger number of cases than any previous cohort study of coffee consumption and colorectal cancer. RESULTS: During an average of 9.6 years of follow up of 61 463 women aged 40-74 years, we observed 460 incident cases of colorectal cancer (291 with colon cancer, 159 with rectal cancer, 10 with cancer at both sites). We found no association between coffee consumption and colorectal cancer risk. The risk ratio for drinking four or more cups per day compared with none was 1.04 (95% confidence interval 0.63-1.69; p for trend 0.84). The findings were similar for cancers of the distal and proximal colon and rectum. CONCLUSIONS: The recently published affirmative conclusions regarding the protective effect of coffee consumption may be premature. For patients seeking advice about coffee consumption, the evidence suggests that moderate or even high consumption will probably not influence the risk of colorectal cancer.
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| 6. |
- Terry, Paul, et al.
(författare)
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Dietary calcium and vitamin D intake and risk of colorectal cancer : a prospective cohort study in women
- 2002
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Ingår i: Nutrition and Cancer. - 0163-5581 .- 1532-7914. ; 43:1, s. 39-46
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Tidskriftsartikel (refereegranskat)abstract
- Although laboratory data and a few adenoma prevention trials suggest that calcium supplementation may reduce the risk of colorectal neoplasia, the results of observational studies of calcium intake and colorectal cancer risk are contradictory. However, few studies have examined the association among women or effects in specific colon subsites. Women with colorectal cancer diagnosed through 31 December 2000 were identified by linkage to regional cancer registries. During an average 11.3 yr of follow-up of 61,463 women, we observed 572 incident cases of colorectal cancer. Using data obtained from a 67-item food frequency questionnaire and Cox proportional hazards models to estimate rate ratios and 95% confidence intervals, we found an inverse association between dietary calcium intake and colorectal cancer risk. Women with the highest calcium intake (median 914 mg/day) had a reduced risk of colorectal cancer (rate ratio = 0.72, 95% confidence interval = 0.056-0.93, P for trend = 0.02) compared with women with the lowest intake (median 486 mg/day). Furthermore, our results suggest that the inverse association may be strongest in relation to distal cancers and among older women. The association with dairy products was less clear, suggesting that calcium intake per se is more important than specific calcium sources. Vitamin D intake was not clearly associated with risk. In sum, our data suggest that high calcium intake may lower colorectal cancer risk.
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| 7. |
- Terry, Paul
(författare)
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Dietary prevention of gastrointestinal cancer : epidemiologic studies of fruit, vegetables and cereals
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The widely accepted inverse associations between fruit, vegetables, dietary fiber and colorectal cancer risk, have recently been called into question. In addition, dietary studies of certain cancers, such as adenocarcinomas of the esophagus and gastric cardia, and prospective cohort studies of stomach cancer, remain scarce. To study cancers of the esophagus, gastroesophageal junction (cardia), stomach, colon and rectum in relation to diet, we analyzed data from three large studies in Sweden: a nation-wide case-control study of cancers of the esophagus and gastric cardia, a nationwide cohort of Swedish twins, and a population-based prospective cohort study of women living in two counties in Central Sweden. We found fruit, vegetables and antioxidants to be inversely related with all of the studied cancers except gastric cardia cancer. For esophageal and cardia cancers, the absolute risk is so low that tens of thousands of people in the highest risk strata of age and sex would need to increase their consumption in order to prevent one case per year. In relation to stomach cancer, our data hint that individuals with very low consumption of fruit and vegetables were at especially high risk. In relation to colorectal cancer, the inverse association was limited to those who consumed very low amounts of fruit and vegetables (less than 2 servings per day). Cereal fiber intake showed an inverse association only with cancer risk only in the gastric cardia. Intake of fiber from fruit or vegetables, on the other hand, was unrelated to cardia cancer risk. We can speculate that nitrosamine-scavenging mechanisms of cereal fiber may be more important in the gastric cardia than elsewhere in the gastrointestinal tract, in turn due to a suggested higher production of nitrosamines in the proximal stomach. While intervention efforts to prevent certain cancer through dietary changes may not be cost effective (such as in the prevention of the rare esophageal cancers), the overall benefit to health, including the prevention of digestive tract cancers, warrants continued efforts to inform and influence the public regarding adequate consumption of these foods.
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| 8. |
- Terry, Paul, et al.
(författare)
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Fruit, vegetables, dietary fiber, and risk of colorectal cancer
- 2001
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Ingår i: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 0027-8874 .- 1460-2105. ; 93:7, s. 525-533
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Several recent large prospective cohort studies have failed to demonstrate the presumed protective effect of fruit, vegetable, and dietary fiber consumption on colorectal cancer risk. To further explore this issue, we have examined these associations in a population that consumes relatively low amounts of fruit and vegetables and high amounts of cereals. METHODS: We examined data obtained from a food-frequency questionnaire used in a population-based prospective mammography screening study of women in central Sweden. Women with colorectal cancer diagnosed through December 31, 1998, were identified by linkage to regional cancer registries. Cox proportional hazards models were used to estimate relative risks. All statistical tests were two-sided. RESULTS: During an average 9.6 years of follow-up of 61 463 women, we observed 460 incident cases of colorectal cancer (291 colon cancers, 159 rectal cancers, and 10 cancers at both sites). In the entire study population, total fruit and vegetable consumption was inversely associated with colorectal cancer risk. Subanalyses showed that this association was due largely to fruit consumption. The association was stronger, however, and the dose-response effect was more evident among individuals who consumed the lowest amounts of fruit and vegetables. Individuals who consumed less than 1.5 servings of fruit and vegetables per day had a relative risk for developing colorectal cancer of 1.65 (95% confidence interval = 1.23 to 2.20; P(trend) =.001) compared with individuals who consumed more than 2.5 servings. We observed no association between colorectal cancer risk and the consumption of cereal fiber, even at amounts substantially greater than previously examined, or of non-cereal fiber. CONCLUSIONS: Individuals who consume very low amounts of fruit and vegetables have the greatest risk of colorectal cancer. Relatively high consumption of cereal fiber does not appear to lower the risk of colorectal cancer.
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| 9. |
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